Area Forecast Discussion
Issued by NWS Glasgow, MT
Issued by NWS Glasgow, MT
863 FXUS65 KGGW 200834 AFDGGW Area Forecast Discussion National Weather Service Glasgow MT 234 AM MDT Wed Aug 20 2025 .DISCUSSION... KEY MESSAGES: - Dangerously hot temperatures are expected over most of NE Montana again today with high temperatures between 95 and 105 degrees. - Somewhat cooler temperatures are expected over Phillips, Petroleum and northern Valley Counties today which will allow the Heat Advisory there to be cancelled. - A cold front tonight will bring chances for showers and thunderstorms with cooler weather Thursday and beyond. WEATHER PATTERN OVERVIEW: The upper ridge moves to the east today with one more day of very hot conditions is expected over most of the region. The thermal ridge will be along the Montana/Dakota border today. While Phillips, Petroleum and northern Valley Counties will be not as hot today with highs in the lower to mid 90s which will allow the Heat Advisory to be cancelled there, the remainder of NE Montana will be very hot again. The Yellowstone Valley and the Missouri Vally east of Fort Peck Lake will have the highest temperatures today with highs between 100 and 105. The cold front will move through the forecast area this evening and tonight with chances for showers and thunderstorms. Hires models are pointing towards gusty and erratic winds with the frontal passage. Winds could reach Lake Wind Advisory criteria for a while this evening over Fort Peck Lake but confidence is too low to issue a Lake Wind Advisory at this time. Surface high moves into the area on Thursday with much cooler temperatures that will prevail through the weekend. FORECAST CONFIDENCE & DEVIATIONS: NBM was used for much of the forecast cycle. Blended in the GFS 1 hour and Hireswfv3 for winds tonight to attempt to factor in the higher winds expected with the cold front. && .AVIATION... LAST UPDATED: 0830Z. FLIGHT CAT RANGE: VFR. DISCUSSION: Hot conditions this afternoon which could lead to Density Altitude issues. Skies will be mostly clear today with some mid and high clouds at times. Mid level clouds are expected tonight with a chance of showers and thunderstorms as a cold front moves through the area. WINDS: KGGW and KOLF, east to NE 5 to 15 knots this morning backing to north to NW this afternoon and tonight. KSDY and KGDV, light and variable early becoming south 10 to 20 knots this morning veering the the SW this afternoon. Winds will become north to NW 5 to 15 knots this evening. In all areas, gusty and erratic winds are possible in any thunderstorm outflows that occur. && .GGW WATCHES/WARNINGS/ADVISORIES... Heat Advisory until 8 PM MDT this evening for Central and Southern Valley-Daniels-Dawson-Eastern Roosevelt-Garfield-McCone- Prairie-Richland-Sheridan-Western Roosevelt-Wibaux. && $$ weather.gov/glasgow